The sheet size detecting device disclosed in Patent Literature 1 includes a pair of side fences, an end fence, a size detection switch, a side-fence rotating member, and an end-fence rotating member.
The size detection switch includes a plurality of push switches. The side-fence rotating member includes a plurality of first projections. The end-fence rotating member includes a plurality of second projections. The plurality of first projections and the plurality of second projections constitute a plurality of composite projections. Depending on the positions of the side fences and the end fence, different composite projections are located opposite to the push switches. Each composite projection pushes a push switch that is located opposite to the composite projection. Therefore, the size of a sheet (hereinafter “sheet size”) can be detected based on the state of the plurality of push switches. The state of the push switches refers to the combination of the states of the respective switches (ON and OFF).
Hereinafter, the side fences and the end fence are generally referred to as “fences”. The side-fence rotating member and the end-fence rotating member are generally referred to as “rotating members”.
Positions of the rotating members may slightly deviate from prescribed positions corresponding to a sheet size. The deviation from the prescribed positions may be caused by structural variation of the components, such as the size detection switch and the rotating members, or by variation in user operations of manipulating the fences. Securing the rotating members at deviated positions may result in error in sheet size detection.
To address the above, a means for correcting a securing position is provided. The securing position correcting means corrects the position of the rotating members to the prescribed positions immediately before the rotating members are secured (position correction). As a result, the positional accuracy of the rotating members improves and error in sheet size detection is prevented.